"Climate Scientists" like Al Gore invoke the phrase "radiative balance" and claim that without the "greenhouse effect" the Earth's temperature would be 33 Celsius colder .
The classic computations here show the maximally biased useless nature
of that assumption . We are 10c warmer than if there were literally no
greenhouse effect .

When these computations are applied to the parameters of Venus , they show James Hansen's claim that its surface temperature is due to a "runaway greenhouse effect" does not compute .

The blue and red curves are the Planck energy , black body , spectra of the sun ,
scaled to our distance from it , and of a black body in
equilibrium with it . The areas under the 2 curves are equal . The
temperature generating the red curve is 278.7 kelvin .

The absorptivity of the earth with respect to the sun's spectrum is
about 0.7 . There is a line across the sun's spectrum at 7 on the
graph . The simple flat , gray , spectrum line is extended
in very light blue across the graph .

Multiplying by 0.7 or any constant clearly
won't change the radiative balance between the blue and red
spectra . Thus a gray ball , no matter how dark or light ,
will come to the same equilibrium temperature . This is the
fact ( Kirchhoff-Stewart ) that I learned as a grade school nerd
during the Eisenhower administration which has driven my battling
this global statist nonscience .The greenhouse effect can be defined as the difference from this temperature due to the color , ie , spectrum , of an object .

The Stefan-Boltzmann law is simply that energy density* is proportional to the 4th
power of temperature . Thus , In order to explain our 3% warmer than
gray observed 288 or so temperature , we have to be about 15% less
absorptive , more reflective , in the long wavelengths than our 0.7
with respect to the sun . The green line continues at the ~ 0.6
that works out to .

For the geeks , the essential relationship computed here it to find temperature T such that

dot[ solar ; objSpectrum ] = dot[ Planck[ T ] ; objSpectrum ]

where objSpectrum is the absorptivity(=emissivity) spectrum of a object , in this case treating the earth as a uniformly colored ball . dot[ ; ] is the dot or inner product : the sum across the products of the two curves .

The black line jumping to 10 ( 1.0 ) in the long wavelengths manifests the ubiquitous assertion that
without greenhouse gases , our planet would radiate as a black body .
It produces a temperature of about 255.7 . This number and 33c greenhouse
effect generated by this calculation has grossly retarded any
progress in climate science . The field , both sides , just
career around in their computational clouds somehow trying to make
sense of a quantity which is 2%3 their own creation .

I think it rather obvious that given any particular full spectrum ,
its radiative balance can be calculated . This balance depends on
its spectrum as seen from the outside , not on how it gets there .
Thus it is open to experimental verification as it has been for more
than a century .

It's when when applying these calculations to Venus came up in a
blog exchange things really got interesting . But I'll leave that to
my End
of 2012 NewsLetter .

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